The impact of social vulnerability on primary vaccine coverage in children with sickle cell disease.

Introduction: This study examines the relationship between social vulnerability and up-to-date (UTD) primary vaccine coverage among children with sickle cell disease (SCD). Methods: This retrospective cohort study included children with SCD born in Georgia between 2008 and 2019, identified through the state newborn screening program. Immunization records were obtained from the state registry, and birth addresses were matched to census tract level Social Vulnerability Index (SVI) scores. Children were considered UTD if they completed the recommended vaccine doses by 24 months. Multivariable logistic regression assessed the association between overall and subtheme SVI scores and vaccine completion, adjusting for demographic and clinical covariates. Results: The study included 1,337 children with SCD. Of these, 37% lived in areas with the highest SVI vulnerability, and 12% lived in the least vulnerable areas. Overall, 58% of children were UTD with their primary vaccine series. Children with moderate or high vulnerability in the socioeconomic subtheme had significantly higher odds of having UTD poliovirus vaccine, measles, mumps, and rubella vaccine, Discussion: Children with SCD are disproportionately concentrated in areas of high social vulnerability. The SVI can help identify neighborhoods for targeted vaccine outreach, especially in communities with high housing and transportation vulnerability. Efforts should prioritize multi-dose vaccines and the varicella vaccine.